CN105261702A - Photoelectronic device and image sensor - Google Patents

Abstract

Example embodiments relate to an organic photoelectric device including a first electrode, a light emitting diode on the first electrode and including a first p-type light-absorbing material and a first n-type light-absorbing material, and an image sensor including the same. an absorbing layer, a light-absorbing auxiliary layer on the light-absorbing layer and including a second p-type light-absorbing material or a second n-type light-absorbing material having a FWHM smaller than a half width (FWHM) of the light-absorbing layer, A charge assisting layer on the light absorption assisting layer, and a second electrode on the charge assisting layer.

Description

Organic optoelectronic devices and image sensors

This application claims the benefit of priority from Korean Patent Application No. 10-2014-0089914 filed with the Korean Intellectual Property Office on Jul. 16, 2014, the entire contents of which are incorporated herein by reference.

technical field

Example embodiments relate to organic photoelectric devices and image sensors.

Background technique

Photoelectric devices typically convert light into electrical signals using the photoelectric effect, may include photodiodes, phototransistors, and the like, and may be applied to image sensors, solar cells, and the like.

Image sensors comprising photodiodes require high resolution and therefore small pixels. Currently, silicon photodiodes are widely used, but typically exhibit degraded sensitivity because of the small absorption area due to the small pixels. Therefore, organic materials capable of replacing silicon have been studied.

Therefore, an organic material capable of replacing silicon may have a high extinction coefficient, or light absorption capability, and may selectively absorb light in a specific wavelength region depending on the molecular structure, and thus may replace both photodiodes and color filters . As a result, the organic material can have improved sensitivity and can contribute to higher device integration.

Contents of the invention

At least one example embodiment relates to an organic photoelectric device capable of improving wavelength selectivity due to improved spectral characteristics.

Another example embodiment relates to an image sensor including the organic photoelectric device.

According to at least one example embodiment, an organic photoelectric device includes: a first electrode; a light absorbing layer on the first electrode and including a first p-type light absorbing material and a first n-type light absorbing material; A light-absorption assisting layer on the layer and including a second p-type light-absorbing material or a second n-type light-absorbing material having a smaller half width (FWHM) than the light-absorbing layer; charges on the light-absorbing assisting layer an auxiliary layer; and a second electrode on the charge auxiliary layer.

The light absorption layer and the light absorption auxiliary layer may be in contact with each other.

The second electrode may be disposed at a side where light enters.

The second p-type light absorbing material or the second n-type light absorbing material may have a FWHM smaller than that of the light absorbing layer by about 5 nm or more.

The external quantum efficiency (EQE) of the second p-type light-absorbing material or the second n-type light-absorbing material at the _maximum absorption wavelength (λmax) may be comparable to that of the light-absorbing layer at the _maximum absorption wavelength (λmax) The external quantum efficiency (EQE) at the same or higher than it.

A FWHM of the light absorbing layer may be wider than a FWHM of the first p-type light absorbing material or the first n-type light absorbing material.

The second p-type light-absorbing material may be the same as or different from the first p-type light-absorbing material, and the second n-type light-absorbing material may be the same as or different from the first n-type light-absorbing material.

The second p-type light absorbing material or the second n-type light absorbing material may be represented by Chemical Formula 1 below.

[chemical formula 1]

In the above Chemical Formula 1,

R ^a -R ^l can be independently hydrogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, halogen atom, halogen-containing groups, or combinations thereof, and

X can be a halogen atom, a halogen-containing group, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C1-C30 aryloxy, substituted or unsubstituted C1-C30 heteroaryloxy, substituted or unsubstituted silyloxy, substituted or unsubstituted amino, substituted or unsubstituted arylamino, or combination.

The first p-type light absorbing material or the first n-type light absorbing material may be represented by Chemical Formula 2 below.

[chemical formula 2]

In the above chemical formula 2,

R ^m -R ^x can be independently hydrogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, halogen atom, halogen-containing groups, or combinations thereof, and

Y is a halogen atom.

The light absorption layer and the light absorption auxiliary layer may absorb light in a green wavelength region.

The light absorption assisting layer may have a FWHM of less than or equal to about 90 nm.

The charge auxiliary layer may substantially not absorb light in a visible wavelength region.

The first electrode and the second electrode may be transparent electrodes, respectively.

According to another example embodiment, an image sensor including the organic photoelectric device is provided.

The image sensor may include integrating a plurality of first photo-sensing devices configured to sense light in a blue wavelength region and a plurality of first photo-sensing devices configured to sense light in a red wavelength region. A semiconductor substrate of a light detection device, and the organic optoelectronic device is on the semiconductor substrate and configured to selectively absorb light in the green wavelength region.

The image sensor may further include a color filter layer including a blue filter configured to selectively absorb light in a blue wavelength region and a red filter configured to selectively absorb light in a red wavelength region. device. The color filter layer may be located between the semiconductor substrate and the organic photoelectric device.

The first light detection device and the second light detection device may be stacked.

The image sensor may include: a green photoelectric device as the organic photoelectric device, a blue photoelectric device configured to selectively absorb light in a blue wavelength region, and a blue photoelectric device configured to selectively absorb light in a red wavelength region. light red optoelectronic device. The green photovoltaic device, blue photovoltaic device, and red photovoltaic device may be stacked.

According to yet another example embodiment, an electronic device including the image sensor is provided.

Description of drawings

1 is a cross-sectional view showing an organic photoelectric device according to at least one example embodiment,

2 is a schematic top plan view of an organic CMOS image sensor according to at least one example embodiment,

FIG. 3 is a cross-sectional view of the organic CMOS image sensor of FIG. 2,

4 is a schematic cross-sectional view of an organic CMOS image sensor according to another example embodiment,

5 is a schematic top plan view of an organic CMOS image sensor according to another example embodiment,

6 is a graph showing the wavelength-dependent external quantum efficiency (EQE) of organic photoelectric devices according to Example 1 and Comparative Example 1,

7 is a graph showing the wavelength-dependent external quantum efficiency (EQE) of organic photoelectric devices according to Example 2 and Comparative Example 2,

8 is a graph showing the wavelength-dependent external quantum efficiency (EQE) of organic photoelectric devices according to Example 3 and Comparative Example 3. Referring to FIG.

detailed description

Example embodiments will be described in detail hereinafter and can be readily performed by those having ordinary knowledge in the relevant art. This disclosure may, however, be embodied in many different forms and is not to be construed as limited to the example embodiments set forth herein.

It will be understood that when an element is referred to as being "on", "connected" or "coupled" to another element, it can be directly on, connected or coupled to the other element. elements, or there may be intermediate elements. In contrast, when an element is referred to as being "directly on," "directly connected to" or "directly coupled to" another element, there are no intervening elements present. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. Further, it will be understood that when a layer is referred to as being "under" another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

It will be understood that although the terms "first", "second", etc. may be used herein to describe various elements, components (components), regions, layers and/or sections (sections), these elements, components (components) , region, layer and/or portion (section) should not be limited by these terms. These terms are only used to distinguish one element, component (component), region, layer or section (section) from another element, component (component), region, layer or section (section). Thus, a first element, component (component), region, layer or section (section) discussed below could be termed a second element, component (component), region, or section without departing from the teachings of example embodiments without departing from the teachings of example embodiments. layer or part (section).

In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. The same reference numbers refer to the same elements throughout. Throughout the specification, the same reference numerals denote the same parts (components).

For ease of description, spatially relative terms such as "under", "beneath", "lower", "above", "upper", etc. may be used herein to describe what is shown in the drawings. The relationship between one element or feature and one or more other elements or features. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" additional elements or features would then be oriented "above" the additional elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a, an" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. It will be further understood that when used in this specification, the terms "comprising" and/or "comprising" indicate the presence of said features, integers, steps, operations, elements and/or parts (components), but do not exclude the presence or addition of One or more other features, integers, steps, operations, elements, parts (components), and/or collections thereof.

Example embodiments are described herein with reference to cross-section illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of example embodiments. As such, deviations from the illustrated shapes as a result, for example, of manufacturing techniques and/or tolerances are to be expected. Thus, example embodiments should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an implanted region illustrated as a rectangle will, typically, have rounded or curved features and/or a gradient of implant concentration at its edges rather than a binary change from implanted to non-implanted region. Likewise, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation occurs. Thus, the regions shown in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of example embodiments.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms such as those defined in commonly used dictionaries should be construed to have a meaning consistent with their meaning in the context of the relevant art, and will not be construed in an idealized or exaggerated sense unless clearly stated herein so defined. As used herein, expressions such as "at least one of" when preceding or following a list of elements modify an entire list of elements and do not modify individual elements of the list.

As used herein, when no definition is otherwise provided, the term "substituted" refers to substitution of a hydrogen of a compound or group with a substituent which is one of the following: halogen (F, Br , Cl or I), hydroxyl, alkoxy, nitro, cyano, amino, azido, amidino, hydrazino, hydrazone, carbonyl, carbamoyl, thiol, ester, carboxyl or their salts , sulfonic acid group or its salt, phosphoric acid or its salt, C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C6-C30 aryl, C7-C30 aralkyl, C1-C4 alkoxy , C1-C20 heteroalkyl, C3-C20 heteroarylalkyl, C3-C30 cycloalkyl, C3-C15 cycloalkenyl, C6-C15 cycloalkynyl, C2-C20 heterocycloalkyl, and combinations thereof.

As used herein, when no specific definition is otherwise provided, the term "hetero" refers to including 1-3 heteroatoms from N, O, S and P.

In the drawings, for clarity of the embodiments, parts that have no relation to the description are omitted, and the same or similar constituent elements are denoted by the same reference numerals throughout the specification.

Hereinafter, the term 'combination thereof' refers to a mixture and/or stacked structure of two or more thereof.

Hereinafter, organic photoelectric devices according to at least one example embodiment are described with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an organic photoelectric device according to at least one example embodiment.

Referring to FIG. 1 , an organic photoelectric device 100 according to at least one example embodiment includes a first electrode 10, a light absorption layer 30 on the first electrode 10, a light absorption auxiliary layer 35 on the light absorption layer 30, a light absorption auxiliary layer 35 on the light absorption The charge assisting layer 40 on layer 35 , and the second electrode 20 on the charge assisting layer 40 . According to at least one example embodiment, one of the first electrode 10 and the second electrode 20 is an anode and the other is a cathode. At least one of the first electrode 10 and the second electrode 20 may be a light-transmitting electrode, and the light-transmitting electrode may be made of or include, for example, a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO) , or thin single-layer or multi-layer metal thin layers. When one of the first electrode 10 and the second electrode 20 is a non-light-transmissive electrode, the non-light-transmissive electrode may be made of or include, for example, an opaque conductor such as aluminum (Al).

For example, the second electrode 20 may be or include a light transmissive electrode.

For example, the first electrode 10 and the second electrode 20 may be or include light transmissive electrodes.

The light absorbing layer 30 may include a first p-type light absorbing material and a first n-type light absorbing material, and may be configured to absorb light from the outside to generate excitons and then separate the generated excitons into holes and electrons.

At least one of the first p-type light-absorbing material and the first n-type light-absorbing material may be or include an organic material, and for example, the first p-type light-absorbing material and the first n-type light-absorbing material Both materials can be or include organic materials.

The light absorbing layer 30 may include an intrinsic layer (I layer) including the first p-type light absorbing material and the first n-type light absorbing material, and may be formed, for example, by co-deposition or the like. In the intrinsic layer, the first p-type light absorbing material and the first n-type light absorbing material may form a heterojunction (bulk heterojunction).

The intrinsic layer may include the first p-type light absorbing material and the first n-type light absorbing material at a thickness ratio of about 1:100 to about 100:1. Within this range, they may be included in a thickness ratio of about 1:50 to about 50:1, about 1:10 to about 10:1, or about 1:1. When the first p-type light absorbing material and the first n-type light absorbing material have a thickness ratio within the range, excitons may be more efficiently generated and a pn junction may be more efficiently formed.

The light-absorbing layer 30 may be a multi-layer including the first p-type light-absorbing material, the first n-type light-absorbing material, or a combination thereof. The light absorbing layer 30 may be or include various combinations, for example, p-type layer/n-type layer, p-type layer/I layer, I layer/n-type layer, and p-type layer/I layer/n-type layer. The p-type layer may include the first p-type light-absorbing material and the n-type layer may include the first n-type light-absorbing material.

The first p-type light-absorbing material and the first n-type light-absorbing material may be configured to absorb light in a visible wavelength region, and the first p-type light-absorbing material and the first n-type light-absorbing material At least one of the materials may be configured to selectively absorb light of a desired or predetermined wavelength region in the visible wavelength region. For example, at least one of the first p-type light-absorbing material and the first n-type light-absorbing material may be configured to selectively absorb light in the green wavelength region, and the light in the green wavelength region It may have an absorption _maximum wavelength (λmax) of about 500 nm to about 600 nm.

In the light absorbing layer 30, the half width (FWHM) indicates the degree of selective absorption of light having a desired or predetermined wavelength region. Here, FWHM is the width of a wavelength corresponding to half of the maximum external quantum efficiency (EQE) in the external quantum efficiency (EQE) versus wavelength diagram. A small FWHM indicates selective absorption of light in a narrow wavelength region and high wavelength selectivity, and a large FWHM indicates absorption of light in a broad wavelength region and low wavelength selectivity.

The first p-type light-absorbing material and the first n-type light-absorbing material may have different spectral profiles, and may have different FWHMs. The light-absorbing layer 30 has a combined spectral curve of the respective spectral curves of the first p-type light-absorbing material and the first n-type light-absorbing material, and the FWHM of the light-absorbing layer 30 is comparable to that of the first p-type light-absorbing material Or the FWHM of the first n-type light absorbing material is wide.

The first p-type light absorbing material or the first n-type light absorbing material may be or include, for example, a compound represented by the following Chemical Formula 2, but is not limited thereto.

[chemical formula 2]

In Chemical Formula 2,

R ^m -R ^x can be independently hydrogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, halogen atom, halogen-containing groups, or combinations thereof, and

Y may be a halogen atom.

Y may be, for example, a fluorine atom or a chlorine atom.

For example, when the compound represented by Chemical Formula 2 is used as the first p-type light-absorbing material, the first n-type light-absorbing material may be or include, for example, a thiophene derivative such as dicyanovinyl-terthiophene (DCV3T), fullerenes, fullerene derivatives, or imide compounds such as Diimide, but not limited thereto.

For example, when the compound represented by Chemical Formula 2 is used as the first n-type light-absorbing material, the first p-type light-absorbing material may be or include, for example, N,N'-dimethylquinacridone (DMQA), N,N'-dimethyl-2,9-dimethylquinacridone (DMMQA), etc., but not limited thereto.

The light absorbing layer 30 may be configured to selectively absorb light in the green wavelength region.

The light absorbing layer 30 may have a thickness of about 1 nm to about 500 nm, and for example, about 5 nm to about 300 nm. When the light absorbing layer 30 has a thickness within the above range, the light absorbing layer may more effectively absorb light, more effectively separate holes from electrons, and transport holes, thereby more effectively improving photoelectric conversion efficiency.

The light absorption auxiliary layer 35 may contact the light absorption layer 30 and may include a second p-type light absorption material or a second n-type light absorption material.

For example, when the first electrode 10 is a cathode and the second electrode 20 is an anode, the light absorption auxiliary layer 35 may include the second p-type light absorption material, and when the first electrode 10 is an anode and the second electrode 20 is a cathode In this case, the light absorption auxiliary layer 35 may include the second n-type light absorption material. The second p-type light-absorbing material may be the same as or different from the first p-type light-absorbing material, and the second n-type light-absorbing material may be the same as or different from the first n-type light-absorbing material.

The second p-type light absorbing material or the second n-type light absorbing material may be selected from materials having a smaller FWHM than the light absorbing layer 30 .

As described above, since the light-absorbing layer 30 has a combined spectral curve of the respective spectral curves of the first p-type light-absorbing material and the first n-type light-absorbing material, the FWHM of the light-absorbing layer 30 is comparable to that of the first p-type light-absorbing material. The FWHM of the p-type light-absorbing material or the first n-type light-absorbing material is wide, and thus the light-absorbing layer 30 has a wavelength selectivity lower than that of the first p-type light-absorbing material or the first n-type light-absorbing material .

In at least one example embodiment, the light absorption auxiliary layer 35 having the second p-type light-absorbing material or the second n-type light-absorbing material having a smaller FWHM than the light-absorbing layer 30 may be set to be smaller than the light-absorbing layer 30. The absorbing layer 30 is closer to the electrode into which light enters, and thus the wavelength selectivity of the light absorbing layer 30 can be compensated.

For example, the second p-type light absorbing material or the second n-type light absorbing material may have a FWHM smaller than that of the light absorbing layer 30 by about 5 nm or more. Within this range, the second p-type light-absorbing material or the second n-type light-absorbing material may have a FWHM smaller than the light-absorbing layer 30 by about 5 nm to about 50 nm, specifically about 10 nm to about 50 nm, and more. Specifically a FWHM of about 10 nm to about 30 nm.

The light absorption assisting layer 35 may have, for example, an extinction coefficient greater than or equal to about 100,000 cm ⁻¹ , and particularly about 120,000-200,000 cm ⁻¹ at the _maximum absorption wavelength (λmax).

The light absorption assisting layer 35 may have, for example, an external quantum efficiency versus wavelength diagram of less than or equal to about 90 nm, about 30 nm to 90 nm for another example, and about 50 nm to about 90 nm for another example.

The light absorption auxiliary layer 35 can maintain or improve the photoelectric conversion efficiency of the light absorption layer 30, and thus the _maximum external quantum efficiency (EQEmax) of the second p-type light absorption material or the second n-type light absorption material can be It is equal to or higher than the _maximum external quantum efficiency (EQEmax) of the light absorbing layer 30 . For example, the maximum external quantum efficiency (EQEmax) of the second p-type light-absorbing material or the second n-type light-absorbing material may be higher than the _maximum external quantum efficiency ( _EQEmax ) of the light-absorbing layer 30 by about 0% to about 30%, such as from about 0.1% to about 30% higher, and for another example from about 1% to about 30% higher.

For example, the second p-type light absorbing material or the second n-type light absorbing material may be represented by the following Chemical Formula 1, but is not limited thereto.

[chemical formula 1]

In Chemical Formula 1,

R ^a -R ^l can be independently hydrogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, halogen atom, halogen-containing groups, or combinations thereof, and

X can be a halogen atom, a halogen-containing group, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C1-C30 aryloxy, substituted or unsubstituted C1-C30 heteroaryloxy, substituted or unsubstituted silyloxy, substituted or unsubstituted amino, substituted or unsubstituted arylamino, or combination.

For example, Table 1 illustrates extinction coefficients and FWHM when in Chemical Formula 1, R ^a to R ¹ are independently hydrogen and X is a group listed in Table 1 below.

(Table 1)

* is the connection point.

The light absorption auxiliary layer 35 may be configured to selectively absorb light in the green wavelength region.

The light absorption auxiliary layer 35 may have a thickness of about 1 nm to about 200 nm. Within this range, the light absorption auxiliary layer 35 may have a thickness of about 5 nm to about 100 nm, and for example, about 5 nm to about 70 nm.

The charge auxiliary layer 40 may be between the second electrode 20 and the light absorption auxiliary layer 35 , and may be configured to allow holes and electrons separated in the light absorption layer 30 to easily migrate to the second electrode 20 . The charge auxiliary layer 40 may substantially not absorb light in the visible wavelength region, and thus does not inhibit absorption of light in the visible wavelength region entering the light absorption auxiliary layer 35 and the light absorption layer 30 from the second electrode 20 side.

For example, when the first electrode 10 is a cathode and the second electrode 20 is an anode, the charge auxiliary layer 40 may be at least one of the following: a hole injection layer (HIL) for promoting hole injection, a hole injection layer for promoting hole A hole transport layer (HTL) for transport, and an electron blocking layer (EBL) for preventing electron transport. When the first electrode 10 is an anode and the second electrode 20 is a cathode, the charge auxiliary layer 40 may be an electron injection layer (EIL) for promoting electron injection, an electron transport layer (ETL) for promoting electron transport, and Hole blocking layer (HBL) to prevent hole transport.

The charge auxiliary layer 40 may include, for example, an organic material, an inorganic material, or an organic/inorganic material. The organic material may be an organic compound having hole or electron properties, and the inorganic material may be or include, for example, a metal oxide such as molybdenum oxide, tungsten oxide, nickel oxide, or the like.

The hole transport layer (HTL) may include, for example, one of the following: poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS), polyarylamine, poly(N -vinylcarbazole), polyaniline, polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (TPD), 4,4'-bis[N-( 1-naphthyl)-N-phenyl-amino]biphenyl (α-NPD), m-MTDATA, 4,4′,4″-tris(N-carbazolyl)-triphenylamine (TCTA), and combinations thereof, but not limited thereto.

The electron blocking layer (EBL) may include, for example, one of the following: poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS), polyarylamine, poly(N- Vinyl carbazole), polyaniline, polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (TPD), 4,4′-bis[N-(1 -naphthyl)-N-phenyl-amino]biphenyl (α-NPD), m-MTDATA, 4,4′,4″-tris(N-carbazolyl)-triphenylamine (TCTA), and combinations thereof, but not limited thereto.

The electron transport layer (ETL) may include, for example, one of the following: 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTCDA), bathocuproine (BCP), LiF, Alq ₃ , Gaq ₃ , Inq ₃ , Znq ₂ , Zn(BTZ) ₂ , BeBq ₂ , and combinations thereof, but not limited thereto.

The hole blocking layer (HBL) may include, for example, one of the following: 1,4,5,8-naphthalene tetracarboxylic dianhydride (NTCDA), bathocuproine (BCP), LiF, Alq ₃ , Gaq ₃ , Inq ₃ , Znq ₂ , Zn(BTZ) ₂ , BeBq ₂ , and combinations thereof, but not limited thereto.

In the organic photoelectric device 100, when light enters from the first electrode 10 and/or the second electrode 20 and the light absorbing layer 30 and the light absorbing auxiliary layer 35 absorb light having a desired or predetermined wavelength region, excitation can be generated from inside. son. The excitons are separated into holes and electrons in the light absorption layer 30 and the light absorption auxiliary layer 35, the separated holes are transported to the anode as one of the first electrode 10 and the second electrode 20, and the separated electrons is delivered to the cathode which is the other of the first electrode 10 and the second electrode 20, so that current flows in the organic photoelectric device.

The organic photoelectric device may be applied to various fields such as solar cells, image sensors, photo-detectors, photo-sensors, and organic light-emitting diodes (OLEDs), but is not limited thereto.

Hereinafter, examples of image sensors including the organic photoelectric device are described with reference to the accompanying drawings. As an example of an image sensor, an organic CMOS image sensor is described.

2 is a schematic top plan view of an organic CMOS image sensor according to at least one example embodiment, and FIG. 3 is a cross-sectional view of the organic CMOS image sensor of FIG. 2 .

Referring to FIGS. 2 and 3 , an organic CMOS image sensor 300 according to at least one example embodiment includes: a semiconductor substrate 110 integrated with a blue light detection device 50B, a red light detection device 50R, a transfer transistor (not shown), and a charge storage 55 , a lower insulating layer 60 , a color filter layer 70 , an upper insulating layer 80 , and an organic photoelectric device 100 .

The semiconductor substrate 110 may be or include a silicon substrate, and may be integrated with a blue light detection device 50B, a red light detection device 50R, a transfer transistor (not shown), and a charge storage 55 . Blue light detection device 50B and red light detection device 50R may be or include photodiodes.

A blue light detection device 50B, a red light detection device 50R, a transfer transistor, and/or a charge storage 55 may be integrated in each pixel, and as shown in the figure, a blue light detection device 50B may be included in a blue pixel and may be in A red light detecting device 50R is included in the red pixel. The charge store 55 is only shown in the green pixel, but the blue and red pixels may also each comprise a charge store connected to the blue light detection device 50B and a charge store connected to the red light detection device 50R.

The blue light detection device 50B and the red light detection device 50R can be configured to detect light, and the information detected by the blue and red light detection devices 50B and 50R can be transferred through the transfer transistor, and the charge memory 55 of the green pixel can be connected with the organic photoelectric device 100 (to be described below) are electrically connected, and the information of the charge store 55 can be transferred through the transfer transistor.

Metal lines (not shown) and pads (not shown) may be on the semiconductor substrate 110 . In order to reduce signal delay, the metal lines and pads may be made of or include metals with low resistivity such as aluminum (Al), copper (Cu), silver (Ag), and alloys thereof, but are not limited thereto . However, the metal lines and pads are not limited to the illustrated structure, and the metal lines and pads may be under the blue and red light detection devices 50B and 50R.

A lower insulating layer 60 may be formed on the metal lines and the pads. The lower insulating layer 60 may be made of or include an inorganic insulating material such as silicon oxide and/or silicon nitride, or a low dielectric constant (low-K) material such as SiC, SiCOH, SiCO, and SiOF. The lower insulating layer 60 may have trenches exposing the charge storage 55 . The grooves may be filled with a filler.

The color filter layer 70 may be on the lower insulating layer 60 . The color filter layer 70 may include blue filters 70B in blue pixels, and red filters 70R in red pixels. In example embodiments, a green filter is not included, but a green filter may be further included.

The upper insulating layer 80 may be on the color filter layer 70 . The upper insulating layer 80 may eliminate steps caused by the color filter layer 70 and may smooth the surface. The upper insulating layer 80 and the lower insulating layer 60 may include a contact hole (not shown) exposing the pad, and a via hole 85 exposing the charge storage 55 of the green pixel.

The organic photoelectric device 100 may be on the upper insulating layer 80 . The organic photoelectric device 100 may include the first electrode 10 , the light absorption layer 30 , the light absorption auxiliary layer 35 , the charge auxiliary layer 40 , and the second electrode 20 as described above.

The first electrode 10 and the second electrode 20 may be transparent electrodes, and the light absorption layer 30, the light absorption auxiliary layer 35, and the charge auxiliary layer 40 may be as described above. The light absorption layer 30 and the light absorption auxiliary layer 35 may be configured to selectively absorb light in a green wavelength region and replace a color filter of a green pixel.

When light enters from the second electrode 20, light in the green wavelength region may be mainly absorbed in the light absorption layer 30 and the light absorption auxiliary layer 35 and photoelectrically converted, while light in the remaining wavelength regions passes through the first electrode 10 and can be detected in blue and red light detection devices 50B and 50R.

As described above, organic photoelectric devices configured to selectively absorb light in a green wavelength region are stacked, and thus, an image sensor can be reduced in size. As described above, the organic photoelectric device 100 can improve green wavelength selectivity due to the light absorption auxiliary layer 35 , and thus can reduce crosstalk typically generated by absorbing light other than in the green wavelength region, and improve sensitivity.

FIG. 4 is a schematic cross-sectional view of an organic CMOS image sensor according to another example embodiment.

Similar to the above example embodiment shown in FIG. 3 , an organic CMOS image sensor 300 according to at least one example embodiment includes integrated blue and red light detection devices 50B and 50R, a transfer transistor (not shown), and a charge storage device. 55 of the semiconductor substrate 110, the insulating layer 80, and the organic optoelectronic device 100.

However, in the organic CMOS image sensor 300 of this example embodiment, unlike in the above example embodiments, the blue light detection device 50B and the red light detection device 50R are stacked in the vertical direction and the color filter layer can be omitted. 70. The blue light detection device 50B and the red light detection device 50R are electrically connected to a charge storage (not shown), and information detected by the light detection devices can be transferred through a transfer transistor.

Depending on the stack depth, the blue light detection device 50B and the red light detection device 50R may be configured to selectively absorb light in each wavelength region.

As described above, the organic photoelectric device 100 configured to selectively absorb light in the green wavelength region is stacked and the red light detection device and the blue light detection device are stacked, and thus, the size of the image sensor can be further reduced. As described above, the organic photoelectric device 100 can improve green wavelength selectivity due to the light absorption auxiliary layer 35 , and thus reduce crosstalk generated by absorbing light other than in the green wavelength region, and improve sensitivity.

FIG. 5 is a top plan view schematically showing an organic CMOS image sensor according to another example embodiment.

According to the example embodiment shown in FIG. 5, the organic CMOS image sensor has a green photoelectric device configured to selectively absorb light in the green wavelength region, a green photoelectric device configured to selectively absorb light in the blue wavelength region A blue photoelectric device, and a red photoelectric device configured to selectively absorb light in a red wavelength region are stacked.

In this figure, red, green, and blue photoelectric devices are sequentially stacked, but example embodiments are not limited thereto, and red, green, and blue photoelectric devices may be stacked in various orders.

The green photoelectric device may be the organic photoelectric device 100 above, and the blue photoelectric device may include electrodes facing each other, a light absorbing layer interposed therebetween and including an organic material configured to selectively absorb light in a blue wavelength region , and the red photoelectric device may include electrodes facing each other, and a light absorbing layer interposed therebetween and including an organic material configured to selectively absorb light in a red wavelength region.

As described above, an organic photoelectric device configured to selectively absorb light in the red wavelength region, an organic photoelectric device configured to selectively absorb light in the green wavelength region, and an organic photoelectric device configured to selectively absorb light in the blue wavelength region Organic photoelectric devices for light in the wavelength region are stacked, and thus the size of the image sensor can be further reduced while improving sensitivity and reducing crosstalk.

The image sensor can be applied to various electronic devices, such as mobile phones, digital cameras, etc., without limitation.

Hereinafter, example embodiments are explained in more detail with reference to examples, but example embodiments are not limited to these examples.

Fabrication of Organic Optoelectronic Devices

Example 1

ITO was sputtered on a glass substrate to form a lower electrode about 100 nm thick. Subsequently, molybdenum oxide (MoO _x , 0<x≦3) and aluminum (Al) were thermally deposited on the lower electrode at a ratio of 1:1 (weight/weight) to form a 5 nm thick electron transport layer (ETL). Subsequently, on the electron transport layer ETL, a compound represented by the following chemical formula 1a (LumTec, LLC) as a p-type light absorbing material, and dicyandiamide as an n-type light absorbing material were co-deposited at a thickness ratio of 1:1. Vinyl-tertiary thiophene (DCV3T) to form a 40nm thick light-absorbing layer. On the light absorbing layer, a compound represented by the following chemical formula 1a is thermally deposited to form a 40 nm thick light absorbing assisting layer, and molybdenum oxide (MoO _x , 0<x≤3) is thermally deposited thereon to form a 5 nm thick charge assisting layer. layer. On the charge auxiliary layer, ITO was sputtered to form a 100 nm-thick upper electrode, and an organic photoelectric device was fabricated.

[chemical formula 1a]

Example 2

An organic photoelectric device was fabricated according to the same method as in Example 1, except that fullerene (C60) was used instead of dicyanovinyl-terthiophene (DCV3T) as an n-type light absorbing material.

Example 3

An organic photoelectric device was fabricated according to the same method as in Example 1, except that: fullerene (C60) was used instead of dicyanovinyl-terthiophene (DCV3T) as the n-type light-absorbing material of the light-absorbing layer, and for For the light absorption assisting layer, a compound represented by the following Chemical Formula 1b was used instead of the compound represented by the above Chemical Formula 1a.

[chemical formula 1b]

The compound represented by the above Chemical Formula 1b was synthesized by the following method.

20.0 g of boronsub-phthalocyanine chloride, 32.0 g of triphenylsilanol, and 14.8 g of trifluoromethanesulfonic acid were heated and refluxed in 150 ml of dry toluene for 15 hours. Then, 200 ml of dichloromethane was added to the resultant, the mixture was filtered, and the filtered solution was concentrated under reduced pressure and purified by silica gel column chromatography to obtain the compound represented by the above Chemical Formula 1b.

Comparative example 1

An organic photoelectric device was fabricated according to the same method as in Example 1, except that the organic photoelectric device did not have a light absorption auxiliary layer.

Comparative example 2

An organic photoelectric device was fabricated according to the same method as in Example 2, except that the organic photoelectric device did not have a light absorption auxiliary layer.

Comparative example 3

An organic photoelectric device was fabricated according to the same method as in Example 3, except that the organic photoelectric device did not have a light absorption auxiliary layer.

evaluate

Evaluation 1: External Quantum Efficiency (EQE) and FWHM

The external quantum efficiency (EQE) and FWHM of the organic photoelectric devices of Examples 1-3 and Comparative Examples 1-3 were evaluated depending on the wavelength.

The external quantum efficiency was measured by using an IPCE measurement system (McScience Co., Ltd. in Korea). First, the measurement system was calibrated by using a Si photodiode (Hamamatsu Photonics K.K. of Japan), and mounted on the organic photoelectric device according to Examples 1-3 and Comparative Examples 1-3, and at a wavelength of about 350-750 nm measure their external quantum efficiencies.

The FWHM is calculated as the width of the wavelength corresponding to half of the _maximum external quantum efficiency (EQEmax) in the external quantum efficiency (EQE) versus wavelength diagram.

The results are provided in Figures 6-8 and Table 2.

6 is a graph showing the wavelength-dependent external quantum efficiency (EQE) of organic photoelectric devices according to Example 1 and Comparative Example 1, and FIG. 7 is a graph showing wavelength-dependent EQE of organic photoelectric devices according to Example 2 and Comparative Example 2. and FIG. 8 is a graph showing the wavelength-dependent external quantum efficiency (EQE) of organic photoelectric devices according to Example 3 and Comparative Example 3.

(Table 2)

Referring to Figures 6-8 and Table 2, compared to the organic optoelectronic device according to Comparative Example 1, the organic optoelectronic device according to Example 1 exhibits comparable or improved external quantum efficiency and narrowed FWHM and thus improved wavelength selection sex. Also, compared with the organic optoelectronic device according to Comparative Example 2, the organic optoelectronic device according to Example 2 exhibited comparable or improved external quantum efficiency and narrowed FWHM and thus improved wavelength selectivity, and compared with the organic optoelectronic device according to Comparative Example Compared to the organic optoelectronic device of Example 3, the organic optoelectronic device according to Example 3 exhibits comparable or improved external quantum efficiency as well as narrowed FWHM and thus improved wavelength selectivity.

Evaluation 2: Crosstalk

The crosstalk of the organic photoelectric devices according to Example 1 and Comparative Example 1 was evaluated.

Crosstalk evaluation was performed via simulation using the LUMERICAL3D program. Here, the wavelength region is divided into three regions of about 440-480nm (blue), about 520-560nm (green), and about 590-630nm (red), and two other photoelectric conversions of different colors in each region are evaluated Optical interference between components. In other words, when the integral of the sensitivity curves of the blue element in the blue region of about 440-480nm is taken as 100, the relative sensitivity curves of the red and green elements in the blue region of about 440-480nm are calculated. integral. The values obtained are for the blue region of about 440-480 nm, the crosstalk of the red and green elements. Likewise, the relative integrals of the sensitivity curves of the red and blue elements in the green region of about 520-560 nm were calculated when the integral of the sensitivity curves of the green element in the green region of about 520-560 nm was considered as 100. This value is for the green region around 520-560nm, the crosstalk of the red and blue elements. Likewise, the relative integrals of the sensitivity curves of the blue and green elements in the red region of about 590-630 nm were calculated when the integral of the sensitivity curves of the red element in the red region of about 590-630 nm was taken as 100. This value is for the red region around 590-630nm, the crosstalk of the blue and green elements. Finally, the crosstalk values are averaged to obtain the average crosstalk.

The results are provided in Table 3.

(table 3)

Average crosstalk (%) Example 1 twenty three Comparative example 1 29

Referring to Table 3, the organic photoelectric device according to Example 1 exhibited an average crosstalk reduction of greater than or equal to about 20% compared to the organic photoelectric device according to Comparative Example 1.

While the present disclosure has been described in connection with what are presently considered to be example embodiments, it is to be understood that the example embodiments are not limited to the disclosed embodiments, but are instead intended to encompass the spirit and scope of the appended claims Various modifications and equivalent arrangements within .

Claims (20)

1. organic electro-optic device, comprising:

First electrode;

On the first electrode and comprise the light absorbing zone of the first p-type light absorbing material and the first N-shaped light absorbing material;

Described light absorbing zone comprises and has the second p-type light absorbing material of the half width (FWHM) less than described light absorbing zone or the light absorption auxiliary layer of the second N-shaped light absorbing material;

Electric charge auxiliary layer on described light absorption auxiliary layer; With

The second electrode on described electric charge auxiliary layer.

2. the organic electro-optic device of claim 1, wherein said light absorbing zone and described light absorption auxiliary layer contact with each other.

3. the organic electro-optic device of claim 1, wherein said second electrode is in the side of light from its incidence.

4. the organic electro-optic device of claim 1, wherein said second p-type light absorbing material or described second N-shaped light absorbing material have the FWHM than the FWHM of described light absorbing zone little 5nm or larger.

5. the organic electro-optic device of claim 1, wherein said second p-type light absorbing material or described second N-shaped light absorbing material are at maximum absorption wavelength (λ _maximum) external quantum efficiency (EQE) at place is equal to or higher than described light absorbing zone at maximum absorption wavelength (λ _maximum) external quantum efficiency (EQE) at place.

6. the organic electro-optic device of claim 1, the FWHM of wherein said light absorbing zone is wider than the FWHM of described first p-type light absorbing material or described first N-shaped light absorbing material.

7. the organic electro-optic device of claim 1, wherein said second p-type light absorbing material and described first p-type light absorbing material identical or different, and

Described second N-shaped light absorbing material and described first N-shaped light absorbing material identical or different.

8. the organic electro-optic device of claim 1, wherein said second p-type light absorbing material or described second N-shaped light absorbing material are represented by following chemical formula 1:

[chemical formula 1]

Wherein

R ^a-R ^lbe hydrogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, halogen atom, halogen-containing group or its combination independently, and

X is halogen atom, halogen-containing group, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C1-C30 alkoxyl, substituted or unsubstituted C1-C30 aryloxy group, substituted or unsubstituted C1-C30 heteroaryloxy, substituted or unsubstituted silicyl oxygen base, substituted or unsubstituted amino, substituted or unsubstituted arylamino or its combination.

9. the organic electro-optic device of claim 8, wherein said second p-type light absorbing material is identical with described first p-type light absorbing material, and

Described second N-shaped light absorbing material is identical with described first N-shaped light absorbing material.

10. the organic electro-optic device of claim 9, wherein said first p-type light absorbing material or described first N-shaped light absorbing material are represented by following chemical formula 2:

[chemical formula 2]

Wherein

R ^m-R ^xbe hydrogen, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C3-C30 heteroaryl, halogen atom, halogen-containing group or its combination independently, and

Y is halogen atom.

The organic electro-optic device of 11. claims 1, wherein said light absorbing zone and described light absorption auxiliary layer are configured to the light be absorbed in green wavelength region.

The organic electro-optic device of 12. claims 1, wherein said light absorption auxiliary layer has the FWHM being less than or equal to 90nm.

The organic electro-optic device of 13. claims 1, wherein said electric charge auxiliary layer is configured to the light be not substantially absorbed in visible wavelength region.

The organic electro-optic device of 14. claims 1, wherein said first electrode and described second electrode comprise transparency electrode respectively.

15. imageing sensors, it comprises the organic electro-optic device any one of claim 1-14.

The imageing sensor of 16. claims 15, wherein said imageing sensor comprises the semiconductor base of the second light detecting device of the first light detecting device and the light of multiple detection in red wavelength region being integrated with the light of multiple detection in blue wavelength region, and

Described organic electro-optic device is on described semiconductor base and be configured to the light that is optionally absorbed in green wavelength region.

The imageing sensor of 17. claims 16, comprise color-filter layer further, described color-filter layer comprises the blue filter being configured to the light be optionally absorbed in blue wavelength region and the red filter being configured to the light be optionally absorbed in red wavelength region, and described color-filter layer is between described semiconductor base and described organic electro-optic device.

The imageing sensor of 18. claims 16, wherein said first light detecting device and described second light detecting device are stacking.

The imageing sensor of 19. claims 15, wherein said imageing sensor comprise stacking as described in organic electro-optic device green light electric device, be configured to optionally be absorbed in the blue light electric device of the light in blue wavelength region and be configured to optionally be absorbed in the red light electric device of the light in red wavelength region.

20. electronic devices, comprise the imageing sensor any one of claim 15-19.